Gas turbine engines are used to power aircraft, watercraft, power generators, and the like. Gas turbine engines typically include a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications.
Economical and environmental concerns, i.e. improving efficiency and reducing emissions, are the main driving force behind the ever increasing demand for higher gas turbine inlet temperatures. A limitation to the efficiency and emissions of many gas turbine engines is the temperature capability of hot section components (example, but not limited to blades, vanes, blade tracks, combustor liners). Technology improvements in cooling, materials, and coatings are required to achieve higher inlet temperatures. As the temperature capability of nickel (Ni)-based superalloys has approached their intrinsic limit, further improvements in their temperature capability have become increasingly difficult. Next generation high temperature materials, such as ceramic-based materials, may be excellent materials for use in gas turbines.
Ceramic based materials such as silicon carbide (SiC/SiC) may replace nickel based superalloys for hot section structural components for next generation gas turbine engines. A benefit of SiC/SiC CMC engine components is their excellent high temperature mechanical, physical and chemical properties which allow gas turbine engines to operate at much higher temperatures than the current engines having superalloy components. SiC/SiC CMCs also provide the additional benefit of damage tolerance, which monolithic ceramics do not possess.